Electronic circuit device

ABSTRACT

An object of the present invention is to provide an electronic circuit device capable of reducing the occurrence of electromagnetic waves associated with the propagation of a signal by utilizing light as a signal. The electronic circuit device has a transparent substrate (hereinafter written as a substrate) over which an optical sensor and an optical shutter and an electronic circuit composed of thin film transistors (TFTs) are formed. An optical signal is inputted from an external into the electronic circuit device, the optical signal is directly irradiated on the optical sensor over the substrate, and penetrates through the substrate, and inputted into an optical sensor over another substrate. The optical sensor converts the optical signal into an electronic signal, and the circuit over the substrate operates. A control signal controls the optical shutter, a light is inputted from the external into this optical shutter, and whether it is transmitted or it is interrupted is determined, whereby the signal is taken out.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an electronic circuit device forlight input, and particularly, relates to an electronic circuit devicefor light input, which is composed by forming a thin film transistor(hereinafter written as a TFT) over a transparent substrate such assubstrate made of quartz, glass, plastic, or the like. Moreover, thepresent invention relates to an electronic device such as a computer orthe like composed of the electronic circuit devices.

[0003] 2. Description of the Related Art

[0004] At the present day, the informatization has been furthermoreadvanced with the improvement of electronic devices. It is expected thatthis tendency will be further promoted hereafter. In general, anelectronic circuit device in wide spread use which configures anelectronic device has the circuit over a printed circuit substrate (alsocalled printed circuit board, hereinafter written as a printed circuitsubstrate). Specifically, a metal such as copper (Cu) or the like isplated over a substrate (also called board) made of glass epoxy or thelike, and then, a wiring for electronic parts is formed by etching it.Then, after the printed circuit substrate has been formed, theelectronic parts such as a Large Scale Integrated circuit (hereinafterwritten as an LSI), a resistance, a condenser or the like are insertedand connected by performing the soldering. As for such a printed circuitsubstrate, the method for fabricating it is easy and is frequentlyapplied.

[0005] Moreover, on the other hand, the performance of electronicdevices has been enhanced from the viewpoint of the operation speed, andfurther enhancement of the operation rate is required.

[0006] In FIG. 3, a conventional electronic circuit device will bedescribed below. The conventional electronic circuit device shown inFIG. 3 is configured with electronic substrates 301, 302, and 303. Theelectronic substrate 301 is fabricated by the procedure that a copperfoil is patterned over a glass epoxy substrate, electronic parts 310 to320 such as a LSI, a resistance, a condenser and the like are arrangedand connected. Electronic substrates 302 and 303 are fabricatedsimilarly. Moreover, the electronic substrate 301 is also inserted intosockets 304, 305 and 306, and the sockets are connected to each othervia wirings 307, 308. And a wiring 309 is connected to an externalcircuit.

[0007] In the conventional electronic circuit devices as describedabove, there have been the following problems. First, there has been acase where a strong electromagnetic wave is generated from an LSI or thelike which are mounted on the electronic circuit substrate. Moreover, astrong electromagnetic wave is also generated in a connecting line forconnecting electronic circuit substrates as well as over the electroniccircuit substrate. There have been problems that such an electromagneticwave has a bad influence on the other electronic parts (not shown) whichis located at the exterior of the electronic circuit device, causesmalfunctions, worsens the performance, and so forth. Such problems havebecome prominent as the electronic circuit operates at a higher rate andas the scale of the electronic circuit is larger.

SUMMARY OF THE INVENTION

[0008] An object of the present invention is to solve the problems suchas a occurrence of noises and a occurrence of malfunctions caused bysuch an electromagnetic wave. Additionally, in the conventionalelectronic circuit units, substrates are connected to one another withwirings; there are limitations to input signals in parallel and thesignal frequency must be set high.

[0009] In order to solve the above-described problems, in the presentinvention, an electronic circuit substrate which configures anelectronic circuit device is configured with a transparent substrate(hereinafter written as a substrate or a transparent substrate), asignal is inputted optically, an optical shutter and an optical sensorare provided and set over the transparent substrate, and a transmissionand reception of a signal are performed using a light, whereby aoccurrence of unnecessary electromagnetic waves is prevented. Further,more parallel processing is enabled by providing a number of opticalsensors and optical shutters which receive light. In this way, thesignal frequency is lowered and the electromagnetic waves can be reducedfurther.

[0010] An electronic circuit device of the present invention comprises aplurality of transparent substrates, and an optical sensor and anoptical shutter are formed over the transparent substrate. An opticalsignal is inputted from an external to the electronic circuit device andthe optical signal is directly irradiated on the optical sensor disposedover the transparent substrate, or the optical signal is transmittedthrough the transparent substrate and inputted into an optical sensordisposed over another substrate. The optical sensor converts the opticalsignal into an electronic signal, and a circuit disposed over thesubstrate is driven. A control signal controls the optical shutter, aninput of light is carried out from the external to this optical shutter,and whether the light is transmitted through the optical shutter or thelight is interrupted is determined, thereby taking out a signal. Thiscontrol signal may be an output of the circuit over the substrate or asignal outputted from another circuit. In this way, an unnecessaryoccurrence of electromagnetic waves is prevented by performing the inputand the output using the optical signal.

[0011] An electronic circuit device having an electronic circuitsubstrate over which an optical shutter and an optical sensor aredisposed is characterized in that the electronic circuit substratecomprises a transparent substrate, an electronic circuit is formed overthe transparent substrate, the electronic circuit includes a pluralityof laminated thin film transistors (hereinafter thin film transistor iswritten as a TFT), an optical signal is inputted from an external, theinputted optical signal is inputted into the optical shutter or theoptical sensor, the optical shutter controls transmission ornon-transmission of the optical signal, and the optical sensor convertsthe optical signal into an electronic signal using the optical sensorand the electronic circuit over the transparent substrate.

[0012] An electronic circuit device having a configuration in which aplurality of electronic circuit substrates are superimposed, wherein anoptical shutter and an optical sensor are disposed is characterized inthat the electronic circuit substrate comprises a transparent substrate,an electronic circuit is formed over the transparent substrate, theelectronic circuit includes a plurality of laminated TFTs, an opticalsignal is inputted from an external, the inputted optical signal isinputted into the optical shutter or the optical sensor over thetransparent substrate, the optical shutter controls transmission ornon-transmission of the optical signal, and the optical sensor convertsthe optical signal into an electronic signal by the optical sensor andthe electronic circuit over the transparent substrate.

[0013] An electronic circuit device having an electronic circuitsubstrate over which an optical shutter and a plurality of opticalsensors are disposed is characterized in that the electronic circuitsubstrate comprises a transparent substrate, an electronic circuit isformed over the transparent substrate, the electronic circuit includes aplurality of laminated thin film transistors, an optical signal isinputted from an external, the inputted optical signal is inputted intothe optical shutter or the optical sensor over the transparentsubstrate, the optical shutter controls transmission or non-transmissionof the optical signal, the plurality of optical sensors convert theoptical signal into an electronic signal by the plurality of opticalsensors and an electronic circuit over the transparent substrate, andthe optical sensor is configured with a plurality of differentsemiconductor layers.

[0014] An electronic circuit device having an electronic circuitsubstrate over which an optical shutter and a plurality of opticalsensors are disposed is characterized in that the electronic circuitsubstrate comprises a transparent substrate, an electronic circuit isformed over the transparent substrate, the electronic circuit includes aplurality of laminated TFTs, an optical signal is inputted from anexternal, the inputted optical signal is inputted into the opticalshutter or the optical sensor over the transparent substrate, theoptical shutter controls transmission or non-transmission of the opticalsignal, the plurality of optical sensors convert the optical signal intoan electronic signal by the plurality of optical sensors and theelectronic circuit over the transparent substrate, the optical sensor isconfigured with a plurality of different semiconductor layers, andcontrolled by TFTs formed with semiconductors which are different fromeach other, respectively.

[0015] The configuration of the electronic circuit device describedabove is characterized in that a TFT of a lowest layer of the pluralityof laminated TFTs is crystallized by a heat treatment, and the TFT ofanother layer of the plurality laminated TFTs is crystallized byirradiating a laser beam.

[0016] The configuration of the electronic circuit device describedabove is characterized in that the plurality of laminated TFTs arecrystallized by a heat treatment.

[0017] The configuration of the electronic circuit device describedabove is characterized in that the heat treatment is a heat treatmentusing a metal catalyst.

[0018] The configuration of the electronic circuit device describedabove is characterized in that the optical sensor over the transparentsubstrate includes an amorphous silicon photodiode, or an amorphoussilicon phototransistor.

[0019] The configuration of the electronic circuit device describedabove is characterized in that the optical sensor over the transparentsubstrate includes a polysilicon (p-Si) photodiode, or a polysiliconphototransistor.

[0020] The configuration of the electronic circuit device describedabove is characterized in that the optical shutter comprising a liquidcrystal which is sandwiched between two transparent substrates.

[0021] The configuration of the electronic circuit device describedabove is characterized in that a polarizing plate is disposed over thetransparent substrate and the polarizing plate is disposed only nearbythe optical shutter.

[0022] In a computer having a plurality of arithmetic and logic unitscomprising a plurality of TFTs which are laminated and formed over atransparent substrate and a plurality of storage devices, exchanges ofelectronic information between the substrates are performed by anoptical shutter and an optical sensor which are controlled by TFTs.

[0023] In a computer having a plurality of arithmetic and logic unitscomprising a plurality of TFTs which are laminated and formed and aplurality of storage devices, exchanges of electronic informationbetween the substrates are performed in parallel by an optical shutterand an optical sensor which are controlled by TFTs.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In the accompanying drawings:

[0025]FIG. 1 is a diagram showing the configuration of an electroniccircuit substrate of the present invention;

[0026]FIG. 2 is a diagram showing an electronic circuit device of thepresent invention;

[0027]FIG. 3 is a diagram showing a conventional electronic circuitdevice;

[0028]FIG. 4 is a circuit diagram of an optical sensor part of thepresent invention;

[0029]FIG. 5 is a schematic diagram showing voltage-currentcharacteristics of a photodiode of an optical sensor part of the presentinvention;

[0030]FIG. 6 is a circuit diagram of an optical sensor part and DFF(Delayed Flip Flop) of the present invention;

[0031]FIG. 7A to FIG. 7F are diagrams showing a timing chart of anoptical sensor part and a DFF (Delayed Flip Flop) of the presentinvention;

[0032]FIG. 8 is a circuit diagram of an optical shutter part of thepresent invention;

[0033]FIG. 9 is a circuit diagram of an optical shutter part of thepresent invention; and

[0034]FIG. 10 is a cross sectional view of an electronic circuitsubstrate of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] [Embodiment Mode]

[0036] Hereinafter, an electronic circuit device of the presentinvention will be described in detail with reference to the drawings.

[0037]FIG. 1 shows a configuration of the present invention. In thepresent invention, an electronic circuit is formed over a transparentsubstrate such as a glass substrate, a quartz substrate, a plasticsubstrate and the like. In FIG. 1, an electronic circuit device of thepresent invention is configured with two transparent substrates 101 and102 but it is possible to superimpose a multiple of such electroniccircuit substrates.

[0038] An optical signal is inputted from an external light source (notshown) into the transparent substrates 102. In FIG. 1, optical signalsare shown as beams 115, 116, and 117 over the transparent substrates 101electronic circuits which are configured with a TFT and the like areformed. In FIG. 1, an electronic circuit is configured with TFTs 104,105, 107, 108, 110 and 111 of CMOS.

[0039] Next, an input of a signal of the present invention will bedescribed below. In the present invention, an input signal is inputtedas an optical signal. In the present invention, an interface for inputand output is configured with an input section and an output section.First of all, a light input section will be described below. An opticalsignal is inputted from external light sources 01 and 02. First, theoptical signal emitted from the light source 01 is transmitted throughthe transparent substrate 102, and irradiated on an optical sensor 112which is disposed over the transparent substrate 101. The optical sensor112 converts the optical signal into an electronic signal, and outputsthe electronic signal which is converted to an electronic circuitdisposed over a layer where a TFT for reset (hereinafter written as areset TFT) 103 is. The optical signal emitted from a light source 02 istransmitted through the transparent substrates 102, and irradiated on anoptical sensor 113. The optical sensor 113 converts the optical signalinto an electronic signal, and outputs the electronic signal which isconverted to an electronic circuit over a layer where a reset TFT 106is.

[0040] In this way, the optical signals inputted from the light sources01 and 02 are converted into electronic signals over the transparentsubstrates by the sensors 112 and 113. Since it is eliminated that anelectronic signal is redundantly decompressed as in the conventionalexample, problems such as noise and the like which have conventionallymattered can be eliminated.

[0041] Next, the configuration of an output section will be described.The output section is a portion that functions to take out outputs ofthe electronic circuit over the transparent substrates to an external.As for an optical signal inputted from a light source 03, it isdetermined whether the optical signal is transmitted through or not byan optical shutter 118 over a transparent electrode 114 controlled by aswitching TFT 109. The optical shutter 118 is controlled by a signal ofan electronic circuit disposed over the transparent electrode 114. Whenthe optical shutter 118 has not transmitted the optical signal, theoptical signal of the light source 03 is not transmitted to theexternal. Moreover, when the optical shutter 118 has transmitted theoptical signal, the optical signal of the light source 03 is transmittedthrough the transparent substrates 101, and outputted to the external.Accordingly, the output of the electronic circuit becomes capable ofbeing fetched to the external.

[0042] As described above, in the present invention, an electric wiringbetween substrates is not used, but an optical signal is used, therebyrealizing a exchange of data of input-output. Owing to this, theproblems such as noises caused by unnecessary electromagnetic waves asdescribed above and the like can be solved.

[0043] What is shown in FIG. 2 is Embodiment Mode in which a pluralityof electronic circuit substrates of the present invention are employed;a plurality of optical paths are disposed over most of the entiresurface of the substrate including a area nearby a center. In this way,in the present invention, different from the conventional printedcircuit substrate in which a signal is taken out with a wiring from endportions of the printed circuit substrate, it is possible to input andoutput signals from anywhere over the transparent substrate as long asthe light is transmitted. Hence, the limitations of the number ofwirings become less compared to those of the conventional printedcircuit substrate, and many signals are capable of being processed inparallel.

[0044] As described above, when the number of signals which areprocessed in parallel is increased, a frequency of the signals iscapable of being lowered. For example, in the case where 100 millions ofdata information units are transmitted per second, if the number of thetransmission paths is 10, 10 millions of data information units must betransmitted through one transmission path, therefore, it is necessary tomake the frequency 10 MHz, but if the number of the transmission pathsis 1000, since only 100 thousands of data information units aretransmitted through one path, the frequency can be lowered to the levelof 100 KHz.

[0045] In this way, the frequency is capable of being lowered since manyparallel processing are capable of being carried out, and theelectromagnetic noises which have been a problem of the conventionaltechniques are capable of further being reduced. Moreover, FIG. 2 showsEmbodiment Mode in the case where a computer is manufactured byutilizing the present invention, and it is configured with transparentarithmetic circuit substrate 201, transparent memory substrates 202, 203and 204. An exchange performed between the arithmetic circuit and thememory circuit can be simplified by carrying out parallel processingusing optical signals. Reference numerals 205, 206, 207 and 208 arearithmetic circuits which function as light interfaces, which receivethe optical signal and convert it into an electronic signal. Referencenumerals 209, 210, 211 and 211 are beams inputted via the lightinterfaces.

[0046] [Embodiments]

[0047] Embodiments of the present invention will be described below.

[0048] [Embodiment 1]

[0049] An optical sensor part will be described in detail. FIG. 4 showsa circuit diagram of an optical sensor part according to the presentinvention. In the present embodiment, the Optical sensor is configuredwith a photodiode. An operation of the optical sensor part will bedescribed below with reference to FIG. 4. First, a reset pulse isinputted into a reset transistor 405. Herein, since a TFT of P-channelpolarity (hereinafter written as Pch) is used for this reset transistor,a signal is active-low. When the reset transistor 405 is turned ON, acathode potential of a photodiode 401 is raised to the level ofpotential of an electric source. At this time, a storage capacitor of acapacitor 402 is also similarly raised to the level of potential of theelectric source. This storage capacitor of the capacitor 402 may not beparticularly mounted when a capacitance of the photodiode 401 is large.Next, a reset pulse becomes high, and the reset transistor 405 is turnedOFF.

[0050] In the case where a light is not inputted, when amount of leakageof the reset transistor 405 and an inverter 403 for buffer issufficiently small, the cathode potential of the photodiode 401 is heldas it is.

[0051] Next, when a light is inputted, a current flows through thephotodiode 401, and the charge of the storage capacitor is drawn to theground (hereinafter written as GND). In this way, the output potentialof the photodiode 401 is going to be lowered when the light is inputted,and is outputted via inverters 403 and 404, which lead to the output ofthe photodiode 401. In FIG. 5, a schematic diagram of the photodiodecharacteristic is shown. When a reverse voltage has been applied to thephotodiode 401, approximately constant electric current flows regardlessof voltage, and the electric current is controlled by an amount of lightirradiated. The electric current increases as the amount of lightirradiated increases. It should be noted that a photodiode of thepresent Embodiment of the present invention is not limited to aphotodiode; a photo detector using other methods might be employed.Specifically, an optical sensor may be formed of amorphous silicon,polysilicon (p-Si), single crystal silicon, or other semiconductormaterials. Moreover, as for an element structure, not only photodiodebut also phototransistor may be used.

[0052] Moreover, in FIG. 6, Example of a circuit in which a plurality ofphotodiodes are used, its data is taken using a latch pulse andmemorized is shown. FIG. 6 shows Example in which a plurality ofcircuits shown in FIG. 4 are disposed, Delayed Flip Flops (hereinafterwritten as DFFs) 610, 611 and 612 are connected after reset transistors601, 602 and 603, photodiodes 604, 605 606, and buffer circuits 607, 608and 609 are connected. FIGS. 7A, 7B, 7C, 7D, 7E and 7F show a timingchart of the circuit shown in FIG. 6. Hereinafter, an operation will bedescribed with reference to FIGS. 7A, 7B, 7C, 7D, 7E and 7F.

[0053]FIG. 7A shows a reset pulse for the purpose of driving the resettransistor 601, and as described above, in the case where a thin filmtransistor having P-channel polarity (hereinafter written as a Pch TFT)is employed for the reset transistor 601, it becomes active-low. Whenthe reset transistor 601 is turned ON, a cathode potential of thephotodiode 604 is raised up to a level of potential of an electricsource. When the reset pulse becomes high, and the reset transistor 601is turned OFF, the behavior after that is changed depending upon whethera light irradiation is carried out or not. FIG. 7C shows an existence ofa light irradiation or non-existence of a light irradiation, in the casewhere the reset pulse is high, it represents that a light irradiation iscarried out, and in the case where the reset pulse is low, it representsthat the light irradiation has not been carried out. FIG. 7D shows thecathode potential of the photodiode 604, and in the case where a lightirradiation has been carried out, the voltage is going to be lowered aswell as the reset transistor 601 is turned OFF.

[0054] In FIG. 7E an output of the photodiode 604 is transmitted throughthe buffer circuit 607, the cathode potential of the photodiode 604 isturned in reverse around the intermediate point between the electricsource and the GND (ground=0), and an output of the buffer circuit 607is changed from a high potential to a low potential. On the other hand,in the case where a light irradiation is not performed, since thephotodiode 604 does not electrically discharge, when the resettransistor 601 is turned OFF, the cathode potential of the photodiode604 is held as it is, and the output of the buffer circuit 607 remainsas it is. FIG. 7B shows a latch pulse, when the latch pulse is high, theoutput of the buffer circuit 607 is inputted into the DFF 610, and theoutput of DFF (shown in FIG. 7F) is held until the latch pulse isinputted subsequently. In this way, the irradiated optical signal isconverted into an electronic signal.

[0055] [Embodiment 2]

[0056] In the present Embodiment, an optical shutter is formed by usingliquid crystal. As is generally known, a liquid crystal panel isfabricated by injecting a crystal liquid material into the cell gap inwidth of several μm, a transmittance of a light is controlled by anapplied voltage and the liquid crystal functions as an optical shutter.The entire surface of a substrate does not need the function of crystalliquid necessarily, however, since the fabrication of the substratebecomes easier when a crystal liquid is injected over the entire surfaceof the substrate, in the present Embodiment, a crystal liquid has beeninjected. Although the fabrication becomes complex, a configuration inwhich the liquid crystal is eliminated from a light input section isalso capable of being employed. In such a case, only a portion where anoptical shutter exists is surrounded with a sealing material, and aliquid crystal may be injected only into that portion.

[0057]FIG. 8 shows a circuit diagram of a portion that is to be anoptical shutter. Since it is not necessary to use an intermediatevoltage as an active drive of a Twisted Nematic liquid crystal(hereinafter written as a TN liquid crystal) which represents a halftone using the intermediate section in the characteristic oftransmittance versus applied voltage, the voltage for applying to theliquid crystal may be binary. Hence, a liquid crystal material which isendurable for a high rate operation such as Ferro Electric LiquidCrystal (hereinafter written as a FLC) and the like, that are endurablefor higher rate operation than a TN liquid crystal is capable of beingused. Needless to say, in the case where a higher response rate is notrequired, a TN liquid crystal and the like may be employed.

[0058] Further, a polarizing plate may be placed over the entire surfaceof an substrate, however, it is preferable that patterning to beperformed and the polarizing plate be placed solely at the opticalshutter part so that a light efficiency to the optical sensor becomeswell.

[0059] In FIG. 8, a liquid crystal element 803 is driven via a buffercircuit constituted of inverters 801 and 802 using a control signalwhich opens and closes the optical shutter. When a switch 804 is turnedON, and a switch 805 is turned OFF, a control signal is at a high value,and when a material which shows normally white mode is used for a liquidcrystal, the liquid crystal optical shutter interrupts a light. When thecontrol signal is at the low value, since the applied voltage to theliquid crystal is 0V, the optical shutter transmits the light.

[0060] Since liquid crystal elements deteriorate when a specific voltageis applied for a long time, the voltage applied to the liquid crystal isturned in reverse by means of switches 804, 805. In this case, since adisplay is not seen by human beings as an usual liquid crystal displaydevice, it is not necessary to turn in reverse at a frequency equal toor more than 60 Hz as a flicker countermeasures. It may be lowerfrequency. Moreover, when it is a liquid crystal material which tends tobe less deteriorated even if a specific voltage is applied, it is alsopossible to stop turning in reverse. Moreover, in the case where theturning in reverse drive of the liquid crystal is performed, it is alsonecessary to turn the control signal in reverse along with the reversesignal.

[0061] In FIG. 9, an example in the case where a DRAM type drive isperformed using a switching transistor and a capacitor so that it may beused in an active matrix type liquid crystal display device is shown. Acontrol signal for opening and closing the optical shutter is inputtedfrom a control signal input 1. Moreover, a signal for writing(hereinafter written as a write signal) a control signal into a liquidcrystal element 906 and a storage capacitor of a capacitor 907 isinputted from a control signal input 2. When a high value is inputtedinto the control signal input 2, a output potential of a buffer circuitconstituted of inverters 903 and 904 is written into a transistor forwriting (hereinafter written as a write transistor) 905, the writetransistor 905 is turned ON, and a potential of the liquid crystal 906is connected to a buffer circuit of the control signal 1, an outputpotential of the buffer circuit constituted of inverters 901 and 902 iswritten into the liquid crystal 906 and the storage capacitor of thecapacitor 907. In this example, it is necessary to refresh by turning ONthe write transistor 905 periodically similarly to the DRAM. Switches908, 909 have a function for the purpose of preventing the liquidcrystal material from being deteriorated similarly to FIG. 8.

[0062] [Embodiment 3]

[0063] The steps according to the present invention will be describedreferring to a cross sectional view in FIG. 10. In FIG. 10, an opticalsensor is configured with a TFT and an amorphous silicon photodiode, andan optical shutter is configured with a crystal liquid. In the presentEmbodiment, the TFT and the photodiode is formed by the followingmethod. First, an overcoating film 1002 is formed over the glasssubstrate 1001. As for this film, an oxide film or a nitride film isformed by a Chemical Vapor Deposition method (hereinafter written as aCVD method). Next, an amorphous silicon is similarly formed into a filmby a CVD method. The amorphous silicon film is crystallized by a laserannealing method, or a thermal annealing method. In this way, apolysilicon (p-Si) film can be formed. Next, TFT islands 1003, 1004 and1005 are formed by patterning the polysilicon film. Then, a gateinsulator 1006 is formed by a CVD method.

[0064] Then, as a method for forming a gate electrode, a metal which isto be a gate electrode is formed into a film by a sputtering methodusing Al (Aluminum), Ta (Tantalum), W (Tungsten) or the like. Afterpatterning and forming gate electrodes 1007, 1008 and 1009, an impurityfor source and drain is doped using a mask by means of a photoresist.After doping an impurity for N-channel polarity (hereinafter written asNch) to the island 1005, and doping an impurity for P-channel polarity(hereinafter written as Pch) to islands 1003 and 1004, the activation ofthe impurities are performed by a laser annealing method or a thermalannealing method. Subsequently, a first inter layer film 1010 is formedand a contact hole is opened.

[0065] Furthermore, source and drain electrodes 1011 are formed byforming metal films for source and drain and patterning them. The metalfilm is composed of a barrier metal and aluminum. A reset TFT and a CMOSTFT for a circuit are formed by the procedure described above. Next, anamorphous silicon film 1012 which is to be a photodiode is formed overthe metal film, and further, as a transparent electrode 1013, Indium TinOxide (hereinafter written as an ITO) is formed into a film, theamorphous silicon film and the ITO film are patterned and etched inseries, thereby forming a photodiode. Next, a second inter layer film1014 is formed and a contact hole is opened. And further, a metal film1015 is formed, and a wiring is formed. The wiring is formed for thepurpose of connecting photodiode electrodes.

[0066] Next, a third inter layer film 1016 is formed and a flattening iscarried out by a Chemical Mechanical Polishing method (hereinafterwritten as a CMP method). Then, amorphous silicon is formed into a film,and the crystallization is carried out by irradiating a laser beam. Atthis time, it is desirable that the laser is not irradiated on theamorphous silicon for photodiode. Islands 1017, 1018 and 1019 are formedby patterning the crystallized silicon. Next, a gate insulator film 1020is formed. Furthermore, a metal film for a gate electrode is formed andpatterned, thereby forming gate electrodes 1021, 1022 and 1023.Subsequently, a p-type impurity is doped to the islands 1017, 1018 and an-type impurity is doped to the island 1019, and then, the activation ofthem is carried out by irradiating a laser beam. Furthermore, a fourthinter layer film 1024 is formed, the contact hole is opened, a metalfilm for source and drain is formed and patterned thereby forming anelectrode 1025. Next, amorphous silicon film 1026 is formed into a filmand an ITO as a transparent electrode 1027 is formed into a film. Then,a photodiode is formed by patterning and etching. Furthermore, a fifthinter layer film 1028 is formed, a contact hole is opened, a metal filmis formed and patterned, thereby forming a wiring 1029. Next, afterforming a sixth inter layer film 1030, a flattening is carried out by aCMP method.

[0067] Furthermore, an amorphous silicon film is formed, and thecrystallization of it is carried out by irradiating a laser beam. Atthis time, it is desirable that the laser beam is not irradiated on theamorphous silicon film 1012, 1026. Next, the silicon is patterned andetched, thereby forming islands 1031, 1032 and 1033. Subsequently, agate insulator film 1034 is formed; a metal film for a gate electrode isformed; patterned and etched, thereby forming gate electrodes 1035, 1036and 1037. Next, a seventh inter layer film 1038 is formed; a contacthole is opened; a metal film for source and drain is formed andpatterned, thereby forming an electrode. Next, an ITO is formed into afilm and patterned, thereby forming a transparent electrode 1040 for theoptical shutter. The substrate on the side of the TFT (hereinafterwritten as a TFT substrate) is completed by the procedure describedabove. Next, a substrate on the opposite side is fabricated. As for acounter substrate, a counter electrode 1042 is formed into a film over aglass substrate 1043. In FIG. 10, although the counter electrode isformed into a film over the entire surface of it, it may be formed onlyover the portion of the optical shutter.

[0068] Although it is not shown, the respective TFTs are capable ofbeing electrically connected with each other by connecting the metallayer of the electrode 1015, the metal layer of the electrode 1021, themetal layer of the gate electrode 1029 and the electrode layer of thegate electrode 1035 via the contact holes. Moreover, the connectionusing a signal is also capable of being optically performed by forming alight-emitting element inside of it.

[0069] Finally, the TFT substrate and the counter substrate are pastedtogether and a liquid crystal 1041 is injected between them and sealed.Owing to this, the liquid crystal over the transparent electrode 1040 iscapable of controlling the transmission and the non-transmission of thelight by controlling the potential of the transparent electrode 1040.

[0070] [Embodiment 4]

[0071] In Embodiment 3, a thin film transistor is formed over a glasssubstrate, however, in the case where quartz substrate is used as atransparent substrate and an optical sensor is formed with a polysilicon(p-Si), a crystallization of the TFTs of the second layer and thereafteris capable of being realized not only by a laser beam but also by SolidPhase Crystallization (hereinafter written as SPC). This is since in aquarts substrate, the substrate shrink is not a problem at SPCtemperature. Moreover, for SPC, a method of crystallizing using a metalcatalyst by utilizing a known method may be employed.

[0072] [Embodiment 5]

[0073] In the present invention, as described above, since theconnection between substrates at any position over a substrate iscapable of being performed using an optical signal, an exchange ofsignals is capable of being carried out without being limited by alayout of the substrates. As for the connection between the arithmeticcircuit and the memory circuit, the exchange of signals is capable ofbeing carried out without using the external bus wirings. Moreover, anumber of exchanges between the substrates can be also markedlyincreased comparing to that of the conventional exchanges usingconventional printed circuit substrates. In this way, by utilizing thepresent invention, a massively parallel processing computer is capableof being configured.

[0074] Since all of the outputs of memory circuits and the like can beoutputted in the orthogonal direction with respect to the transparentsubstrate in a parallel processing computer using the present invention,the conventional failures in taking out the memory contents in serialorder, that is, for example, such problems as the frequency increasing,a circuit for calling becoming complex and the like can be solved.

[0075] As described above up to this point, in the present invention, anelectronic circuit is formed with a TFT over a transparent substratemade of glass or plastic, not over a printed circuit substrate, and aelectromagnetic noises generated from a signal line of an electroniccircuit are capable of being reduced by utilizing an optical signal, notusing an electronic signal for inputting and outputting signals.Moreover, conventionally, the input and output of a signal have beenperformed into and from the periphery of the printed circuit substrate,however, in the present invention, since input and output of a signal iscapable of being performed into and from any position over the substrateby transmitting an optical signal, a parallel processing of the signalis capable of being carried out. In this way, the present invention hasan effect of being capable of performing more parallel processing bymeans of optical signals.

[0076] It will also be appreciated that, although a limited number ofembodiments of the invention have been described in detail for purposesof illustration, various modifications may be made without departingfrom the spirit and scope of the invention. Accordingly, the inventionshould not be limited except as by the appended claims.

What is claimed is:
 1. An electronic circuit device comprising: anelectronic circuit substrate over which an optical shutter and anoptical sensor are disposed, said electronic circuit substratecomprising: a transparent substrate; and an electronic circuit includinga plurality of laminated thin film transistors formed over saidtransparent substrate, wherein an optical signal is inputted from anexternal, said inputted optical signal is inputted into said opticalshutter or said optical sensor; and wherein said optical shuttercontrols transmission or non-transmission of said optical signal, andsaid optical sensor converts said optical signal into an electronicsignal using said optical sensor and said electronic circuit over saidtransparent substrate.
 2. The electronic circuit device according toclaim 1, wherein the thin film transistor of a lowest layer of theplurality of laminated thin film transistors is crystallized by a heattreatment, and the thin film transistor of another layer of theplurality of laminated thin film transistors is crystallized byirradiating a laser beam.
 3. The electronic circuit device according toclaim 1, wherein the plurality of laminated thin film transistors arecrystallized by a heat treatment.
 4. The electronic circuit deviceaccording to claim 2, wherein the heat treatment is a heat treatmentusing a metal catalyst.
 5. The electronic circuit device according toclaim 3, wherein the heat treatment is a heat treatment using a metalcatalyst.
 6. The electronic circuit device according to claim 1, whereinsaid optical sensor over said transparent substrate includes anamorphous silicon photodiode, or an amorphous silicon phototransistor.7. The electronic circuit device according to claim 1, wherein saidoptical sensor over said transparent substrate includes a polysilicon(p-Si) photodiode, or a polysilicon phototransistor.
 8. The electroniccircuit device according to claim 1, wherein said optical shuttercomprises a liquid crystal which is sandwiched between two transparentsubstrates.
 9. The electronic circuit device according to claim 8,further comprising a polarizing plate, wherein said polarizing plate isdisposed over said transparent substrate, and said polarizing plate isdisposed only nearby said optical shutter.
 10. An electronic circuitdevice comprising: a configuration in which a plurality of electroniccircuit substrates are superimposed, an optical shutter and an opticalsensor are disposed, said electronic circuit substrate comprising: atransparent substrate; and an electronic circuit including a pluralityof laminated thin film transistors formed over said transparentsubstrate, wherein an optical signal is inputted from an external, saidinputted optical signal is inputted into said optical shutter or saidoptical sensor over said transparent substrate, and said optical signalis converted into an electronic signal by said optical sensor and saidelectronic circuit over said transparent substrate.
 11. The electroniccircuit device according to claim 10, wherein the thin film transistorof a lowest layer of the plurality of laminated thin film transistors iscrystallized by a heat treatment, and the thin film transistor ofanother layer of the plurality of laminated thin film transistors iscrystallized by irradiating a laser beam.
 12. The electronic circuitdevice according to claim 10, wherein the plurality of laminated thinfilm transistors are crystallized by a heat treatment.
 13. Theelectronic circuit device according to claim 11, wherein the heattreatment is a heat treatment using a metal catalyst.
 14. The electroniccircuit device according to claim 12, wherein the heat treatment is aheat treatment using a metal catalyst.
 15. The electronic circuit deviceaccording to claim 10, wherein said optical sensor over said transparentsubstrate includes an amorphous silicon photodiode, or an amorphoussilicon phototransistor.
 16. The electronic circuit device according toclaim 10, wherein said optical sensor over said transparent substrateincludes a polysilicon (p-Si) photodiode, or a polysilicon photodiode.17. The electronic circuit device according to claim 10, wherein saidoptical shutter comprises a liquid crystal which is sandwiched betweentwo transparent substrates.
 18. The electronic circuit device accordingto claim 17, further comprising a polarizing plate, wherein saidpolarizing plate is disposed over said transparent substrate, saidpolarizing plate is disposed only nearby said optical shutter.
 19. Anelectronic circuit device comprising: an electronic circuit substrateover which an optical shutter and a plurality of optical sensors aredisposed, said electronic circuit substrate comprising: a transparentsubstrate; and an electronic circuit including a plurality of laminatedthin film transistors formed over said transparent substrate, wherein anoptical signal is inputted from an external, said inputted opticalsignal is inputted into said optical shutter or said optical sensor oversaid transparent substrate; wherein said plurality of optical sensorsconvert said optical signal into an electronic signal by said pluralityof optical sensors and said electronic circuit over said transparentsubstrate; and wherein said optical sensor is configured with aplurality of different semiconductor layers.
 20. The electronic circuitdevice according to claim 19, wherein the thin film transistor of alowest layer of the plurality of laminated thin film transistors iscrystallized by a heat treatment, and the thin film transistor ofanother layer of the plurality of laminated thin film transistors iscrystallized by irradiating a laser beam.
 21. The electronic circuitdevice according to claim 19, wherein the plurality of laminated thinfilm transistors are crystallized by a heat treatment.
 22. Theelectronic circuit device according to claim 20, wherein the heattreatment is a heat treatment using a metal catalyst.
 23. The electroniccircuit device according to claim 21, wherein the heat treatment is aheat treatment using a metal catalyst.
 24. The electronic circuit deviceaccording to claim 19, wherein said optical sensor over said transparentsubstrate includes an amorphous silicon photodiode, or an amorphoussilicon phototransistor.
 25. The electronic circuit device according toclaim 19, wherein said optical sensor over said transparent substrateincludes a polysilicon (p-Si) photodiode, or a polysiliconphototransistor.
 26. The electronic circuit device according to claim19, wherein said optical shutter comprises a liquid crystal which issandwiched between two transparent substrates.
 27. The electroniccircuit device according to claim 26, further comprising a polarizingplate, wherein said polarizing plate is disposed over said transparentsubstrate, said polarizing plate is disposed only nearby said opticalshutter.
 28. An electronic circuit device comprising: an electroniccircuit substrate over which an optical shutter and a plurality ofoptical sensors are disposed, said electronic circuit substratecomprising: a transparent substrate; an electronic circuit including aplurality of laminated thin film transistors formed over saidtransparent substrate, wherein said optical sensor is configured with aplurality of different semiconductor layers, and controlled by thin filmtransistors formed with semiconductors which are different from eachother, respectively; and wherein an optical signal is inputted from anexternal, said inputted optical signal is inputted into said opticalshutter or said optical sensor over said transparent substrate, and saidplurality of optical sensors convert said optical signal into anelectronic signal by said plurality of optical sensors and saidelectronic circuit over said transparent substrate.
 29. The electroniccircuit device according to claim 28, wherein the thin film transistorof a lowest layer of the plurality of laminated thin film transistors iscrystallized by a heat treatment, and the thin film transistor ofanother layer of the plurality of laminated thin film transistors iscrystallized by irradiating a laser beam.
 30. The electronic circuitdevice according to claim 28, wherein the plurality of laminated thinfilm transistors are crystallized by a heat treatment.
 31. Theelectronic circuit device according to claim 29, wherein the heattreatment is a heat treatment using a metal catalyst.
 32. The electroniccircuit device according to claim 30, wherein the heat treatment is aheat treatment using a metal catalyst.
 33. The electronic circuit deviceaccording to claim 28, wherein said optical sensor over said transparentsubstrate includes an amorphous silicon photodiode, or an amorphoussilicon phototransistor.
 34. The electronic circuit according to claim28, wherein said optical sensor over said transparent substrate includesa polysilicon (p-Si) photodiode, or a polysilicon phototransistor. 35.The electronic circuit device according to claim 28, wherein saidoptical shutter comprises a liquid crystal which is sandwiched betweentwo transparent substrates.
 36. The electronic circuit device accordingto claim 35, further comprising a polarizing plate, wherein saidpolarizing plate is disposed over said transparent substrate, saidpolarizing plate is disposed only nearby said optical shutter.
 37. Acomputer comprising: a plurality of arithmetic and logic units and aplurality of storage comprising a plurality of thin film transistorswhich are laminated and formed over a transparent substrate, whereinexchanges of electronic information between said substrates areperformed by an optical sensor and an optical shutter controlled by thinfilm transistors.
 38. A computer comprising: a plurality of arithmeticand logic units and a plurality of storage devices comprising aplurality of thin film transistors which are laminated and formed over atransparent substrate, wherein exchanges of electronic informationbetween said substrates are performed in parallel by an optical sensorand an optical shutter controlled by thin film transistors.